This invention relates in general to wheelchairs and, in particular, to wheelchair accessories. Most particularly, the invention relates to an axle mounting plate for mounting a drive wheel to a wheelchair side frame.
Axle mounting plates are well known. A typical axle mounting plate is a flat plate that is adapted to be supported in a vertical orientation between two longitudinally spaced rear vertical tubes of a wheelchair side frame. The flat plate is typically affixed to each one of the vertical tubes with conventional fasteners, such as hex head fasteners. The plate is usually provided with a series of vertically spaced holes or a series of vertically spaced longitudinally extending slots. These slots extend longitudinally, that is, in a direction between the front of the wheelchair and the back of the wheelchair. An axle, or an axle sleeve, can be inserted into any one of the slots and fixed to the plate. This permits the elevation of the frame to be adjusted relative to a supporting surface. By spacing the slots discrete distances apart, the elevation of the frame can be adjusted by discrete amounts. The axle or the axle sleeve can also be fixed to the plate at any point along the slots. This permits the distance between the caster and the rear drive wheel, or the wheelbase, to be adjusted. These adjustment features permit a wheelchair occupant or attendant to fine-tune the center of gravity of the wheelchair.
A problem with a conventional axle mounting plate is that it requires two rear vertical side frame tubes in spaced relation to one another. Such a plate is cumbersome to attach because the plate must be held adjacent the vertical tubes while inserting the fasteners through the plate and the tubes. Quite often, a nut must be held in place while the fastener is tightened. This could be a physical challenge to a wheelchair occupant with limited dexterity.
Another problem with a conventional axle mounting plate is that it can only be attached to rear vertical tubes of the side frame. This limits the amount of adjustment of the drive wheels to the configuration of the plate, since the plate cannot be moved relative to the side frame. The drive wheel axle may be adjusted relative to the plate but the plate cannot be adjusted relative to the side frame.
Yet another problem with a conventional axle mounting plate is that such a plate is typically made of steel due to its strong structural composition, a characteristic typically not found in lighter-weight materials. Steel is an expensive material that may require a considerable amount of time to tool. Steel is also subject to effects of corrosive elements.
What is needed is a low cost, user-friendly axle mounting plate that accommodates a greater level of adjustment and that is resistant to corrosion.
The present invention is directed towards an axle mounting plate that meets the foregoing needs. The axle mounting plate comprises a main body portion. A first coupling extends from the main body portion. A second coupling extends from the main body portion. The first and second couplings each defines a generally C-shaped saddle. The saddles are generally at 90 degrees relative to one another. An axial sleeve is provided through the main body portion.
In another embodiment of the invention, an axle mounting comprises a main body portion, first means for coupling the main body portion to a portion of the side frame, second means for coupling the main body portion to a portion of the side frame, means for receiving an axial, and means for reinforcing the said main body portion and said axial receiving means.
In yet another embodiment of the invention, a wheelchair has a side frame having a first tube and a second tube transverse to said first tube. An axle mounting plate comprises a main body portion. The main body portion has a first coupling engaging said first portion of said side frame. A second coupling engages a second portion of the side frame. The first and second portions of the side frame are transverse relative to one another. An axial sleeve is provided through the main body portion. A drive wheel has an axle supported by the axle sleeve.